Plastic tray design details:Design Stations
The key point is whether the tray stacking design has a fool-proof mechanism.

Ordinary tray plate design: plane tray plus card ditch, then stack tray stack.
When the upper tray tray is removed,
the lower tray tray may be attached,
and a slight amount of deformation may suck/snap to the lower tray tray.
In addition to designing sop to teach factory workers to stagger stacking tray trays,
in practice, errors often occur, causing damage to the contents.
The only advantage is the flat tray tray design is relatively simple and inexpensive.
However, subsequent use issues are worth considering.

Key Design Techniques: Design Stations
Do not press the product on the tray when stacking.
It is recommended that the stack height be more than 10mm apart.
Usually there will be legs, but the cost is higher.
It also reduces the contact area in the stack.
This station is designed with a good fool-proof mechanism
and requires no additional education and training.